This invention relates to a novel resist composition adapted for microfabrication, and a patterning method.
A number of efforts are currently made to achieve a finer pattern rule in the drive for higher integration and operating speeds in LSI devices. Deep-ultraviolet, x-ray and electron beam lithography processes are thought to hold particular promise as the next generation in microfabrication technology. Deep-UV lithography is capable of pattern generation to dimensions of 0.25 xcexcm or less and, when a resist material having low light absorption is used, can form patterns with sidewalls that are nearly vertical to the substrate. One technology that has attracted a good deal of attention recently utilizes a high-intensity KrF or ArF excimer laser as the deep-UV light source. Resist materials with low light absorption and high sensitivity are needed to successfully apply this technology to large-volume production.
In conjunction with the demand for higher integration, higher operating speeds and finer pattern rules in LSI devices, an attempt has also been made to increase the diameter of substrates. There is a desire to have a resist composition which when applied to current mainstream 8-inch substrates, forms a coating having a thickness uniformity, free of defects, and wettable with an aqueous base developer, and which has a good storage stability in that particles do not increase during storage in solution form.
In light of this, acid-catalyzed chemical amplification type resist materials were recently developed. As the large-scale manufacture technology of these resist materials advances, their problems of applicability, wettability and storage stability become outstanding.
An object of the invention is to provide a novel and improved resist composition which when combined with large-scale manufacture technology, forms a coating having a thickness uniformity, free of defects, and wettable with an aqueous base developer, and which has a good storage stability in that particles do not increase during storage in solution form. Another object is to provide a patterning method using the resist composition.
According to the invention, there is provided a resist composition comprising a fluorochemical surfactant. When the resist composition is coated onto a substrate to form a coating, fluorochemical surfactant functions to reduce the contact angle at the interface between the surface of the resist coating and water or an aqueous base developer as the amount of the fluorochemical surfactant added increases. The fluorochemical surfactant is preferably of the general formula (1) defined later. This resist composition eliminates the inconveniences of resist material with respect to applicability, wettability, and storage stability.